Static discharge device



'Feb. 16, 1943. v H. M. HUCKE 2,311,608

smxc DISCHARGE nmvrcs Filed May 10, 1940 2 Sheets-Shani. l

' Ffih. i5, 1%43. HUCKE STATIC DISCHARGE DEVICE 2 Sheets-Sheet 2 Filed May 1G 194} f/grberf Hue/r? Patented Feb. 16, 1943 i Q g gg ng UNITED STATiiiii OFFiCE Herbert M. Hucke, Arlington, Va, assiguor to United Air Lines Transport Corporation, Chicago, 111., a corporation oi Application May 10, 19%, Serial No. 334,il9 12 Claims. (01. NS -264) This invention relates to the subject of static order to damp oscillatory currents, a resistor dissipation and more particularly to the disis placed at some point between the craft and the charging of static electricity from aircraft durconductors. The novel device of the present ining flight. vention is well adapted to utilize this solution to Pilots flying under certain atmospheric condiproblem of static dissipation. tions, such as snow, dust and rain storms, have Une of the objects of the present invention is experienced extreme difllculty in receiving of rato provide a mechanism capable of installation dio range signals and communication from the upon aircraft which will eliminate the interiorground due to the presence of a unique static ence due to snow static. condition, as a result of which intelligible signals it: Another object of the invention is the proviare often completely masked, rendering radio resion of a novel mechanism by which the precipiceptior. extremely difficult and often impossible. tation of static charges may be effected with Due to the importance of radio as a means of facility and dependability. communication with the ground and as an in- (Ether objects of the invention include the prostrument of navigation, extended study has been 15 vision of a novel mechanism for effecting static made of the conditions producing static disturbdischarge, which can be easily installed upon a ances oi the above types, which are often recraft and stored until it is needed to discharge ierred to as snow static. As a result of the inthe craft, which can be readily operated by a vestigation o! the origin of snow static, it has pilot during flight, which gives an indication of been determined that a craft, in flying through operation to the pilot and which can be readily the air, assumes a definite electrical potential renewed and replaced.

with respect thereto, which potential may vary @ther objects'will appear from a reading oi with atmospheric conditions and which may be the specification when studied in conjunction on the order of thousands of volts, Charged par with the attached drawings in which like nuticles of snow, rain, dust and other matter sus merals refer to like parts throughout.

pended in air, in striking the fuselage and wings Fig. i represents he mechanism of one cm of an all metal plane, impart their individual bodiment of the present invention, partly in charges thereto and these accumulate and in secross-section and elevation as installed upon an rious conditions of snow static, the total charge aircraft;

on the craft becomes so great that salient points 3 3, Fig. 2 is a showing in elevation of a portion oi and surface parts of small diameter, such as the mechanism of the present invention as it appropeller tips, wing tips, and the trailing edges pears when fully extended in. flight;

of the wings and empennage, for example, go into Fig 3 is a schematic diagram of the electric corona and cause arcing over between diiferent circuits used in the present invention; and portions of the craft. The existence of arcs on Fig. 4 is a detailed showing in perspective of the craft causes excessive interference with radio a portion of the present invention.

reception, and for the duration of the arcing con- In general terms, the present invention comdition renders radio receivers useless quite often prises a static discharge device which is mounted at times when reception is of the greatest imp0rin compact form within a receptacle in a trailtance to the safety of the pilot and the passening portion of an aircraft and which, by means ers. of a control panel at the pilots position in con- One solution which has been applied as a result junction with a novel indicating circuit, gives an of the above investigations, is the discharging oi indication as to the condition of the operativesnow static at a point removed from and rearness of the static discharge device. By means of wardly of the craft. The excessive charge which a switch, the pilot places the discharge means in causes arcing is led by means of a conductor of operation at any time that he encounters static comparatively large diameter to the rear oi the conditions and he is constantly advised of the craft, a distance of about five feet, and it is then operation of the discharge device by a novel indiallowed to flow to a conductor of relatively fine cator within the cockpit.

gauge. The first conductor is made of such a Having reference to Fig. 1, H1 represents a diameter that it will not go into corona for the receptacle in a trailing portion of an aircraft, charges encountered, and the second conductor such as the tail, having apertures H and I2 is made of a very small diameter, so that it will adapted to receive tubular metal cartridge or go into corona at a poinaqubstantlally lower than shell members i3 and i4. These cartridge memthe corona point of any portion of the aircraft. to oers are identical and hereafter corresponding parts of each will be identically numbered. One cartridge carries suilicient mechanism for sails factory operation of the novel device of the present invention, but two cartridges may be provided for reasons to be described later. At the innermost end of receptacle it there are provided resilient locking means II, which are not only fixed to the receptacle by any conventional means such as bolts, but which are also grounded elec= trically to the receptacle and the body of the aircraft. Plug member I8 is carried upon end wall I! of each of the cartridges l3 and i4 and cooperates with locking member it so as to make a quick connect and disconnect arrangement. Mounted upon a transverse wall Ii, which is spaced from wall II by straps is, there is a cy lindrical sleeve member 2a welded or otherwise attached to wall member id at one end. Slidable axially of sleeve 20 is a hollow tubular plungei member 2|, having connected to one end an enlarged generally frustro-conical head 22, and at its other end an annular insert 23 having a shoulder 24 against which a helical spring 25 abuts. The other end of spring 25 is seated against a ring member 28, which is attached in ternally oi sleeve 20 and rigidly connected, along with sleeve 20 to the transverse wall member is. concentrically with axially movable plunger ii, there is a rod member 21, rigidly connected to an annular collar 29 by welding or any suitable means, and the assembly of collar 28 and rod 271 is maintained in fixed position concentrically of plunger 2i by means of screws or studs 28 which engage with ring member 28 through transverse wall member ll. The annular insert 28 is slid-= able along the rod 21 to a rearward position in which itengages a collar member Ma secured to said rod at the rear end thereof. A pillar member 38, having an open, slotted end as shown more clearly in Fig. 4, is welded or otherwise fixed to wall member II and pivotally holds a latch or trigger it. As shown in cartridge i3, latch or trigger member 3i engages with a wire yoke member 82 which is connected in any conventional manner to annular insert 23. Trigger Si is maintained in enga ement with wire yoke 32 by means of wire link 33 which is a relatively strong, yet fusible wire such as music wire on the order of .01 inch in diameter.

A series of longitudinal rods 36, concentric with rod member 11, are equl-distantly disposed about the surface of wall it and are rigidly welded, or otherwise attached thereto. In the embodimentshown, five of these rods are used and for a reason to be described later, any odd number of rods 34 may be used. These rods are also connected to a spacer member such as metal plate ll, in order to support them intermediate their ends, and rods 34 therefore not as a frame upon which is coiled an electrical conducting unit made up of a resistor 36 of a composition to be described later, and a fine wire 37 connected to one end of resistor, by any conventional connector, such as crimped metal member The other end of electrical resistor it passes through a cutout portion of wall it, which por tion is shown most clearly in Fig. 4, and is connected to a terminal 39, which is electrically grounded to wall I! and to the aircraft through plug IGL The outer end of wire 3? is connected,

as shown in dotted lines, to a cord or other flexible member 4|, which is connected to cord menu bers ll, forming a bridle to which is attached a wind-cone I2.

In order to provide a positive seat for bridle member ii, head 22 is slotted as indicated at 43. Wind-cone 42 can be of any slightly resilient material, such as parchment, oil paper, etc., having an annular bead 44 adapted to cooperate with cam members 5 to retain wind-cone 42 in its normal position upon the plunger head 22.

An annular ring 46 is removably attached to cartridges l8 and I4 by means of a bayonet Joint or any other conventional fastening means. Stretched across the, mouth of cartridge i3 and retained in place by ring 48, is a frangible sealing member Bl of parchment, oiled paper, or the like. for keeping rain, snow and other foreign matter from entering the interior of the cartridge, and

one--hundredths of an inch, but these approximate dimensions may, of course, vary with dii ferent installations and are such that for the charges expected to be encountered, no substantial corona discharge will occur along resistor 3S and practically all corona discharge will be confined to wire 31. Resistor 36 and wire 37 may each have a length on the order of five feet.

Resistor 38 is composed of a fibrous, flexible, rope-like material, such as jute or hemp, impregnated with colloidal graphite, such as commercially available under the name "Aquadag. Over this body of impregnated jute or hemp is placed, by extrusion, molding or any other proccos, a watertight covering of rubber or the like material. The whole assembly results in a novel type of resistor which may, depending upon the process of treatment, have a resistance on the order of fifty thousand ohms per foot'of length. As stated above, an odd number of rods 34 is provided. With this arrangement, wire 3lcan as indicated in the cross-section of Fig. 1, and

this arrangement provides an advantageous means for obviating the improper winding of wire 3! within the cartridge. With the arrangement shown, there can be no crossing over of turns and thus, when the wind-cone is projected into the slip-stream, wire 31 will be paid out without the possibility of knotting.

Spring 25 should have suillcient strength to be capable of ejecting plunger 2! in a forceful manner upon the fusing of wire link 83 and COIISE} quent release of yoke member 82 by trigger 3!, so that the frangible diaphragm 41 may be easily broken and the wind-cone 42 projected safely into slip-stream, even though ice or other formation has completely .covered the mouth of aperture it or 52. When plunger 2! reaches the end of its rearward movement, as limited by engagement oi annular insert 23 with collar member Ella, wind-cone 52 is projected far enough into the slip-stre to exert the required tension to withdraw wire 37 and resistor 88 from the cartridge, and thereafter will maintain them in extended position.

A feature of the embodiment of the invention and wire 31 are maintained taut in the slipstream of the craft by means of wind cone 52. As

shownin Fig. 4, resistor 36 passes over switch arm 9, which is made of any spring metal, and the tension of resistor 36, in its ejected position, causes spring switch arm 48 to be movedaxially until it contacts terminal 50, thereby closing an indicating circuit to be described below.

The plug member I. carries two insulated sleeve contacts I and 52 which, when in operative position, engage with suitable brushes such as 53 and 54, respectively. The sleeve contact M is electrically connected through an insulated stud member did to the contact member 50, and the sleeve contact 52 is connected through an insulated stud member 2a to the end of the wire link 33 opposite that which is connected to the trigger 3|, which latter is rounded.

Having reference particularly to Fig. 3, there are shown electric circuits which not only enable the pilot to eject the static discharge conductor assembly, but also indicate the condition of the assembly before and after ejection. Duplicate circuits are provided for the cartridges l3 and I4, including test and release switches 55 and 58, respectively, located on a control panel accessible for operation by the pilot. Tracing the circuit shown for cartridge l3, it will be noted that when the pilot's switch 5! is thrown over to the contact marked Test," either the light marked "Out" or Set' will illuminate. If the plunger II has not ejected the dissipator assembly, tension switch II will be open and fusible link 33 will be closed, causing current to flow from battery through the Set light, brush 54. contact 52, stud 52a and fusible link 31 to ground and back to battery, indicating that the cartridge is ready for operation. If he now throws switch ii to the release position, current will flow from battery through brush it without illuminating either of the indicating lights, through contact 52, stud 52a and fusible link 33, to ground and back to battery. This circult does not contain an indicating light. and the wire link 33 is so designed that it will fuse when the voltage drop. due to an indicating-light, is not in the circuit, as in this condition more current will flow through said link.

After wind-cone 41 has completely withdrawn resistor 38 and wire 31 from the cartridge, which condition is shown for cartridge ll of Fig. l. the electric circuit for this condition is shown in the bottom part of Fig. 3. Tension switch 48 is now closed and fusible link 33 is now broken and, upon V the pilot's throwing switch 56 to the Test" position, an electric circuit will be completed from battery through Out light, illuminating the same, through brush 63, sleeve contact 5|, stud Ha, contact 50, switch 48 and plug it to ground. thence back to battery.

It will be readily understood that the pilot can be continuously advised of the position and condition of the dissipator assemblies and in the event that the proper release of one cartridge is not effected, for example, in the event that the wind-cone or resistor I6 and wire 31 might be whipped off, the pilot can then release a second cartridge l4, and he is thereby afforded an additional factor of safety. It is for this reason that Fig. 1 shows an assembly of two cartridges. and the control panel shown in Fig. 3 has duplicate switches 55 and I8 and duplicate indicating lights and circuits. to permit the pilot to operate the particular cartridge which is to be utilized for static dissipation.

It will also be understood that the cartridge assemblies such as 13 and H are readily'removable and replaceable so that renewed units can be quickly inserted in place of units which have been released for use during flight. The construction of the plug member I and cooperating locking members I5 is such as to provide a secure mechanical as well as electrical connection of the cartridge members in place. while still permitting ready engagement and disengagement of the same by proper manipulation thereof. Units which are removed after use are readily and economically renewable by simply replacing and resetting the parts subject to rupture or possible damage, including the wire links 33 and diaphragxns 41, and also the wind-cones 42, cords 40 and II, wires 31, and resistors II in case the latter parts are damaged either during flight or upon landing.

Since it,,is not intended to restrict the inven-- tion to the particular embodiment shown, various changes can be made without exceeding the scope of the invention. For example, any other suitable resistance material, or form of resistance, might be substituted for resistor 38, and any desired modifications within the skill of the art are to be understood as comprehended by the appended claims.

What is claimed is: 1. Apparatus for the dissipation of static charges, comprising a receptacle mounted upon a vehicle, a cartridge removably fitted within said receptacle and containing an ejector mechanism, quick-detachable means for securing saidcartridge in said receptacle and electrically connects ing said cartridge to said vehicle, an electric conductor having one end electrically connected to said vehicle through said cartridge and its other end positioned so as to be carried by said ejector mechanism. trigger means within said cartridge for normally retaining said ejector mechanism in retracted condition, and means operable within said vehicle for effecting operation of said trigger means in said cartridge to release said ejector mechanism and eject said electrical conductor from said cartridge.

2. In combination, means for discharging static from an aircraft comprising a receptacle mounted on said aircraft, a cartridge removably secured within said receptacle, an electrical conductor within said cartridge; means within said cartridge for ejecting said conductor therefrom,

an electrical connection between said conductor if said aircraft, means operated from said aircraft to initiate the ejection of said conductor, and means within said aircraft and operated by said conductor to indicate the ejection of said conductor from said receptacle.

3. Mechanism for controlling the discharge of static from an aircraft which comprises a receptacle mounted on said aircraft, a cartridge carried by said receptacle, an electrical conductor within said cartridge and having one end electrically connected thereto, an ejector mechanism within said cartridge, means upon said mechanism for carrying the other end of said conductor, a fixed frame mounted axially of said ejector mechanism and extending longitudinally thereof, said conductor being wound about said frame, trigger means for normally holding said ejector mechanism in retracted position, means within said aircraft for actuating said trigger means and thereby causing said conductor to be ejected, and means operated by said conductor when in ejected condition for indicating said condition within said aircraft.

4. In combination with a vehicle subject to static charges, means forvcontrolling the dissipation of such charges comprising an electrical conductor having one end electrically connected to said vehicle, its otherend extending rear wardly at some length from said vehicle, an electrical resistor disposed between the ends of said conductor, means for containing said conductor normally coiled within a trailing portion of said vehicle, means within said trailing portion for ejecting said conductor, means for normally holding said ejecting means in retracted position, and means operable from within said vehicle to release said ejecting means, whereby said conductor will extend rearwardly of said vehicle as above specified.

5. An apparatus for the dissipation of static charges, comprising a cartridge adapted to be mounted within the trailing portion of an aircraft, a spring-biased plunger within said cartridge, a latch for normally maintaining said plunger retracted against the action of its spring, a fusible link for maintaining said latch member in plunger restraining position, an electrical conductor coiled within said cartridge and ha'v in: one end connected to said aircraft, a windcone carried by said plunger, a lead connecting said wind-cone to the free end of said electrical conductor, and electrical switch means for fusing said fusible link, whereby said latch releases said spring-biased plunger to project said wind-cone into the slip-stream of the aircraft and start the uncoiling of said electrical conductor.

6. Apparatus for discharging static from an aircraft in flight, comprising a hollow tubular member adapted to be carried in a trailing por= tion of an aircraft, a plug attached to the inner end ofsaid member for engaging with a looking means on an aircraft, an electrical conductor coiled within said member and having one end electrically connected to said plug, a windcone within said member connected to the other end of said conductor, a plunger and spring means for ejecting said plunger from said member, latch means for maintaining said plunger retractedagainst the action of said spring means, means carried by said wind-cone for releasably connecting said wind-cone to said plunger, means for tripping said latch means, whereby, upon ejection of said-plunger by the action of said spring means, said wind-cone may be projected into the airstream and eifect the uncoiling of said conductor, and means operable upon the uncoiling of said conductor for indicating the operation of said apparatus within said aircraft.

7. Apparatus for discharging static from an aircraft in flight, comprising a hollow tubular member adapted to be carried in a trailing portion of an aircraft, a plug attached to the inner end of said member for engaging with a locking means on an aircraft, an electrical conductor coiled within said member and having one end electrically connected to said plug, a wind-cone within said member connected to the other end of said conductor, a plunger and spring means for ejecting said plunger from said member, latch means for maintaining said plunger retracted against the action of said spring means, means carried by said wind-cone for releasably connect-. ing said wind-cone to said plunger, means in cluding an electrically fusible link for tripping said latch means, whereby, upon ejection of said plunger by the action or said spring means, said wind-cone may be projected into the airstream 8. Apparatus for the discharge of static from i an aircraft in flight, comprising a receptacle in a trailing portion of said aircraft, a hollow tubu- 18.1 cartridge releasably connected within said receptacle, static discharge means releasably held within said cartridge, electric circuit-changing means within said cartridge actuated by the operation of said static discharge means, and indicating means in circuit therewith, including means within said aircraft for indicating a change of circuit.

9. An apparatus for the dissipation of static charges comprising a cartridge adapted to be secured to a trailing portion of an aircraft, plunger means in said cartridge, means for biasing said plunger for movement from a retracted position to a projected position, latch means for normally maintaining said plunger means in said retracted position, a wind-cone carried by the projectable end of said plunger means, conductor means coiled within said cartridge having one end connected to said aircraft and the other end connected to said wind-cone, and means for releasing said latch means to free said plunger for movement to said projected position to project said wind-cone into the slip stream of the aircraft and start the uncoiling of said conductor taro-responsive latch means in said cartridge for normally maintaining said plunger means in said retracted position, a wind-cone positioned in said cartridge for movement therefrom by said plunger means, conductor means coiled within said cartridge having one end electrically and mechanically. connected to said cartridge and the other end mechanically connected to said windcone, and means within said aircraft for effecting operation of said electro-responsive latch means; to release said plunger means and project said wind-cone into the slip stream of the aircraft, said plnger means thereby starting the meching of said conductor means.

11. Apparatus for discharging static from an aircraft in flight comprising a hollow tubular tion of an aircraft, interengaging locking means on said trailing portion and said member respectively, said locking means on said member including a plug, an electric conductor coiled within said member and having one end electrically connected to said plug, a plunger within said member, spring means for ejecting said plunger from said member, latch means for maintaining' said plunger retracted against the action ofsaid spring means, a wind-cone within said member connected to the other end of said conductor and releasably associated with said plunger for movement thereby, and means for tripping said latch means to cause ejection of said plunger and movement of said wind-cone into the slip from said member, latch means for maintaining said plnuger retracted against the action of said spring means, a wind-cone within said membe:- connected to the other end 0! said conductor and releasably associated with said plunger for movement thereby, and means including an electrically fusible element for tripping said latch means, whereby, upon ejection of said plunger by said spring means, said wind-cone is projected into the air stream to effect uncoiling of said conductor.

HERBERT M. HUCKE. 

